Numerous studies have documented how characteristics of the social environment are related to alcohol consumption and the types of problems associated with alcohol dependence. Studies have also shown that the characteristics of clients' living situations are factors associated with treatment outcome. Sober living houses provide individuals with an alcohol and drug free living environment who attempting to establish or maintain sobriety. They have been used as aftercare placements for clients completing residential treatment, places for clients to live while attending outpatient treatment, or as referral sources for individuals in the criminal justice system. However, the research on sober living houses has been limited and no research has tracked measures of resident functioning over time. The primary aim of this study is to investigate longitudinal outcomes of individuals in sober living residences. Data will be collected during in-person interviews at entry into the residence, and 6-month, 12-month, and 18-month follow-up time points. Effectiveness will be measured in terms of 6-month measure of alcohol and drug use, criminal justice involvement, housing stability, employment, and Addiction Severity Index composite scores. Pre-post comparisons will be made for the overall sample as well as three subgroups of residents: those who completed residential treatment, those who are attending outpatient treatment with no residential treatment the past year, and those who were referred from the criminal justice system. The study also will assess whether demographic characteristics, psychopathology, motivation for change, involvement in formal treatment, a ratio of adjunctive services received to services desired, or various social support measures predict outcome. Finally, comparisons will be made between individuals residing in sober living houses and a group of individuals referred to sober living residences who left within the first week. This research will provide a longitudinal description of how well residents in sober living houses function in a variety of areas. It will also describe the mix of formal treatment and informal social support activities that these individuals utilize, and will correlate these activities with outcome. Finally, it will demonstrate whether sober living residents have better outcomes than a comparison group of similar individuals.